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(No Model.)

J. W. EASTON. ELECTRIC ARC LAMP.

NQ. 448,418. Patented Mar. 17, 1891.

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'Lhtrrnn STATES PATENT OFFICE.

JAMES XV. EAS"O1.\, OF NElY YORK, N. Y., ASSIGNOR TO 1. MINTURN SMITH, OF PLAINFIELD,NEW .TEESEY,1 ND WILLIAM D. PERRY, OF BROOKLYN,

NEYV YORK.

ELECTRlC-ARO LAMP.

SPECZFICATIGN forming part of Letters Patent No. 448,418, dated March 17', 1891.

Eerial No. 344,592. (No model.)

To all "whom it hwy concern.-

Be it known that I, Janus WArsoN EASTON, a subject of the (Queen of Great Britain, and a resident of the city, county, and State of New York, have invented certain new and useful Improvements in Electric Lamps; and I hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming part of this specification.

My'invention relates to electric-arc lamps, and the object thereof is the automatic regulation of the movement of the carbon-feeding devices.

To this end it consists in the novel means and mechanism for controlling the movement of the carbon-rod, and in the novel details of construction and arrangement and combina tion of parts hereinafter shown, described, and claimed.

In the accompanying drawings, Figure l is a side, and Fig. 2 a front, elevation of the parts of an electric-arc lamp embodying my invention; and Fig. 3 is a view, partially in section, showing the details of a portion of the feed-controlling devices.

Similar letters of reference are used in all the views to designate corresponding parts.

The upper carbon A of the lamp is clamped in any suitable manner to the carbon-rod B, to which is also secured a rack Z). A pinion 0, arranged to engage with said rack, is mounted upon a shaft 0, journaled in a frame or lever D,which is supported on pivotal bearings d, suitably attached to the framework of the lamp. Upon the shaftc is also rigidly secured the wheel it arranged to revolve with the pinion C. To the end d of the frame D. or to a projection d thereof, is connected one end of a spiral spring F, the helices f of which are drawn apart or separated from each other for a portion of the length of the spring, as clearly shown in the drawings. The other end of the spring F is suitably se cured to an adjusting-screw G, attached to the frame-work of the lamp. The periphery of the wheelE is preferably grooved, as shown, and the elongated helices of the spring are arranged to lie in said groove. It will thus be seen that said spring 1 forms a brake which governs the movement of the wheel E. The other end of said frame D is provided with a projecting pin (Z which engages with a hole or slot in the core II of a differential solenoid composed of a high-resistance coil ll, arranged in a shunt of the main or are circult of the lamp, and alow-resistance coil H included in the main circuit of the lamp. It

is apparent that if the wheel E were left free to revolve the carbon A and rod 13 would descend by their own weight, and the carbons would thus be brought together. \Vheu no current is on the lamp and the frame D is in the position shown in Fig. 1, the wheel E is free to revolve, the tension of spring F being insufficient to counteract the weight of the carbon and carbon-rod, and the carbons therefore come together. If new the current be turned on, a circuitis completed through them, which includes the coil H Said coil is thereby energized and attracts the core II, which lifts the end of the frame D, connected thereto, and depresses the opposite end (Z. By this movement of frame D the helicesfare brought into more intimate contact with the periphery of wheel E, producing sufficient friction thereon to prevent its rotation. At the same time the pinion O is lifted by the movement of frame D, carrying with it the carbon-rod l3, separating the carbons 8o slightly,and thereby formiugthe arc and lighting the lamp. Then by the consumption of the carbons the arc becomes too long, the resistance of the arc circuit is thereby sufficiently increased to shunt a portion of the current through the high-resistance coil H, whereby the core ll is attracted thereto, lifting the end (1 of frame D. This permits the spring 15 to contract, the helices thereof all moving toward the stationary end of the 0 spring. During the beginning of the upward movement of the end (1 of frame D this movement of the helices will carry the wheel E in the same direction, the tension of the spring affording the requisite pressure of the helices 5 upon the periphery of the wheel for that purpose. If, however, this upward movement of the frame D be continued, the tension of the spring is reduced sufficiently to actually release the wheel and permit it to revolve zoo freely. By the revolution of wheel E in this direction the carbon-rod B is permitted to descend and the carbon A approaches the lower carbon until the arc is of the proper length, when the resistance of the arc circuit is decreased, coil h is tie-energized, and core H is attracted by coil H whereby the revolution of wheel E is checked by the tightening of spring F, produced by the downward movement of end d of the frame D. When the length of the arc again exceeds the proper limit, the operations just described are re peated.

The other features of the lamp and their operation are well known to those skilled in the art and do not require further description here.

Although I prefer to construct the brake F in the form of a spring substantially as shown, I do notwish to limit n1yself.theret0, because any construction whereby the desired degree of elasticity can be obtained will probably answerand constitute an equivalent for said spring. A simple lever might also be used instead of the frame D; but I prefer the construction shown,because it affords a firm bearing for the pinion and brake-Wheel shaft. Electro-magnets and an armature may also, if desired, be substituted for the solenoids and core shown and described.

The chief advantages of my invention are its simplicity, durability, and delicacy of operation.

Heretofore a pawl-and-ratchet movement has generally been used to control the movement of the feeding devices in lamps of this character. With such devices the minimum rained.

the carbon-rod and a spiral spring bearingagainst the periphery of said wheel, one end of said spring being secured to a fixed portion of the lamp or frame and the other end beingconnected with the core or armature of a solenoid or magnet, whereby the tension of said spring is varied with changes in the resistance of the lamp-circuit, substantially as and for the purposes set forth.

2. In an electric-arc lamp, the combination of the carbon-rod provided with a rack,a pin'- ion adapted to engage therewith, a brakewheel rigidly secured to the shaft carrying said pinion, a spiral spring bearing against the periphery of said wheel, and means, substantially as shown, for varying the length of said spring in accordance with the resistance of the lamp-circuit, substantially as shown and described.

3. In an electric-arc lamp, the combination of the carbon-rod, a rack secured thereto, a pinion adapted to engage with said rack, a wheel arranged to revolve with said pinion, a spiral spring bearing against the periphery of said wheel, a lever connected with, said spring, a differential solenoid the core of which is connected with said lever, and mechanism, substantially as shown, for adjusting the tension of said spring, substantially as and for the purposes set forth. a

JAMES W. EASTON.

Witnesses:

CHAS. A. MURPEEY, S. G. METCALF. 

